This is a tool for debugging the performance of a website. It is a web extension, so it is enabled in all web browsers. It's a convenient app that supports a small number of websites.

However, the developer is working on a version for more websites. It is a tool that overlays an image on top of your website. It is a bit like a photo frame. This image is a tool for understanding the performance of a website.

The extension provides a lot of details about the website, allowing users to know more about the vital annotations.